Signaling system for railroads



BY M 46 $4 ATTORNEY July 28, 1936. w. H. REICHARD SIGNALING SYSTEM FOR RAILROADS Filed Jan. 18, 1935 q |||||1 m N-./ 832 1W 4 o n an m 4 6 N. 8 @T L :J mm WH IFIM FIQITIHTA v U- E-I E m n .r e fil 0 m Yu .0 II J. o CHE IL m NA All 1 Patented July 28, 1936 warren STATES SIGNALING SYSTEM FOR RAILROADS Wade H. Reichard, Rochester, N. Y., assignor to General Railway Signal Company, Rochester,

Application January is, 1935, 'Serial' No. 2,391

6 Claims.

This invention relates to signaling or train control systems for railroads, and moreparticularly to improvements in cab signaling andtrain control'systems of the continuous inductive control type whereby the operation of the trackrelays is automatically checked and train operation safeguarded in the event of failure of a track relay to respond to the presence of a train.

Generally speaking, in accordance with this in- 10 vention, it is proposed to add to the usual and well-known system of block signaling or continuous inductive control cab signaling or train control system, an organization of relays and circuits for checking the operation of the track relays in such a way that failure of'the track relay to respond to the presence of a train will give a restrictive indication for following trains.

In the usual system of signaling or train control, the presence of a train in a given section of track is detected by the shunting and de-energi- .zation of a track relay; andif this track relay i should for any reason happen to fail to respond to the presence of the train, clear indications would be improperly displayed for following trains. While such a failure of a track relay occurs only very rarely and under unusualor exceptional circumstances, it is proposed to provide additional safety by checking the operation of the track relays.

Various characteristic features, adaptations, functions, and advantages of the invention will be in part apparent and in part explained as the description progresses.

The accompanying drawing .illustrates in a simplified and diagrammatic manner one. specific the usually normally energized track. circuit, and

that some suitable form of automatic blocksignal system with wayside signals, and/or continuous inductive control cab signaling or train con trol will be provided. Such systems of signaling or train control may take various forms; and the simple types shown are merely illustrative.

Referring to the drawing, the track rails l are divided by insulated joints 2 into blocks in the usual way, one block B with the ends of adjacent blocks A and C having been shown; The equipment foreach block is the same, and an explanation of such equipment for the block B will suffice for all. At one end of the block B, preferably at the entering end (traffic being from left to right as indicated by the arrow), a track relay TB isconnected across the track rails in the usual way. As illustrated, it is assumed that this track relay will be of the usual direct current type, and that in addition to the track circuit current, the rails 5 of the block B will be supplied with alternating current for cab signal or train control purposes. Accordingly, the secondary of a transformer 3, in series with the, track battery 4, is connected across the track rails at the exit end of block B. 10

Associated with the track relay for each block is a special stick relay, designated SE for the block B, and SC for the block C. Similarly, special stick relays VB'and VC are associated with the blocks B and C. 15

Also associated with each block in the embodiment of the invention illustrated, is a motor driven coder M employed to interrupt the alternating current supplied to the track rails at different rates of and 180 times per minute, for 20 example, for each to control either train control or cab signals, or both. The cab signaling and/or train control current is assumed to be of a distinctive frequency, suchas cycles supplied from a suitable transmission line L energized 25 from a generatorG.

As typical of a wayside block signal contemplated in accordance with this invention, a simple two-indication color light signal has been shown conventionally at the entrance of each of 30 the blocks B and C.

V The energizing circuits for the various relays have been shown conventionally, with connections to the terminals of suitable batteries or other sources of current and to a common wire indi- 35 cated by the symbols plus minus and C. The various electrical circuits are more conveniently traced in connection with the explanation of the operation.

The parts are shown in the drawing in the 40 normal clear condition when no trains are present. The track relays of the blocks are energized in the usual way. The stick relays SB and SC are assumed to have been properly restored by some previous train, in a manner later to be 45 explained, and having been so restored, are normally energized by a stick circuit including a front contact 5 of such stick relay and a front contact 6 of the corresponding track relay, this stick circuit being readily traced on the drawing. 50 The other stick relays VB and V0, conveniently termed the code starting relays, are normally deenergized and the corresponding coders M are de-energized and inactive. The indications of the wayside signals are controlled by contacts 55 lished from plus through the back contact 1 of the track relay TB, front contact 8 of relay 7 SB, line. wire 9, through relay VCv to the common wire C and back to the battery, presumably located at the entrance to the block B. Inthis connection, it will be noted that this pick-up circuit for the code starting relay V0 is estab-.

lished only during the time after the track relay drops and before the stick relay SB is deener- 'gized; and the stick relay SB is made suificiently slow releasing, with respect to the pick-up time of relay VC, that said relay VC will'be effectively energized. When the relay V0 is energized, it is maintained energized by a stick circuit through back contact "I of track'relay TB, over the line wire IE], front, contact II of relay VC, wire I2,

through the winding of relay VC' to the common return'C. 7

Thus, the entrance. of the train into the block B de-energizes relay SB and energizes the code starting relay V0 for the block B. The de-energization of the stick relay SB opens the circuit for the proceed lamp-G of the wayside signal at the entrance to block B, and closes the circuit forlighting the lamp giving the stop indication R. The energization of relay VC. supplies current to the motor M to intermittently close the coding contacts l3 and I4, assumedto provide rate codes of 80 and '180' per minute. The energization of the relay VC also closes its front contact l5 so'that' alternating rail current may be supplied to the block B. Assuming the block C to be unoccupied, this ran current for block B is interrupted at the 180 code rate, the. circuit for energizing the primary of transformer 3 being from the lower transmission line, wire 16, front contact l5 of {relay VC, wire l1, coder contacts l4, wire I8, front contact IQ of track relay TC,

wire 29, front contact 2l. of stick relay SC, Wire 22, primary of transformer 3, and wire 23 to the other transmission line wire L.

When the train in question advances into. the block C, and assuming that the track relay TC of this block is properly de-energized, the stick relay SC isde-energi'zed and the code starting relay in the next blockin advance (not shown) is energized in the same manner as already described. The de energization of the relay SC causes the wayside signal at the entrance tothe block C to indicate stop, and also connects, through the back contact 2| of said relay SC and wire 24, the coder contacts I3 into a circuit for supplying rail current to the block B of the 80 code, thus causing a restrictive indication to be displayed on any following train in the block B.

The de-energization of the track relay TC by the entrance of the train into the block C, and

'after this train has cleared the block B so that .lishes 'a pick-up-circuit for relay SB which may be traced from plus through the back con- .tact 25 ofthe track relay TC, line wire. 26, front contact 21 of the track relay TB, wire 28 to relay waysidesignal at the entrance to the block SB, and thence through the common return wire C bacl; to the battery. Thus, if the track relay TC of the block C is operated properly, stick re- I lay SB at the entrance to the next block B in the rear is restored to change the indication of 5 the wayside signal at the entrance to that block, and also to change the code rate for the rail current supplied to the block A to 180 for proceed upon picking up of relay VB.

When the train leaves the block B,,the code starting relay VC is deenergized, both its pickup and stick circuits being broken at the back contact I of the track relay TB, and the coder M for block B stops. 7 V

- "To explain the safety or checking feature af- 15 forded by this invention, assume that the track relay TC in the block C for some reason fails to release its armature; If such an exceptional condition should occur, an improper proceed indication would be given with the usual type of 20 wayside signaling and cab signaling system. With the'safety feature of this invention, how ever, when track relay TC failed to drop, the pick-up circuit for restoring the stick relaySB for block B is not established but is open at contact 25 of TC and said relay SB' remains deenergized. .This leaves a stop indication displayed by. the wayside signal at the entrance to the block B. Also, if axfollowing train should enter the block B, the .code starting relay V0 30 would not be energized, its pick-up circuit being broken at the'front' contact 8 of relay SB; and

thereiwould be no alternating rail current supplied to the block B and thus, with train control, apply the-brakes, and with cab signals, result in a red signal.

Thus, if the track relay of a block fails to respond to thepresence of a train, a'stop indication is given in the block in the rear, although that block is not occupied. Additional safety is thus provided in the event of a track relay failure, trains. approaching the block with the defective track relay being'givena restrictive indication. a In the event'of such track circuit failure, the

block with the defective track relay, due to the shunting effect of the wheels and axles of the train ahead. This invention, therefore aifordse. fmoreadditional safety when used in conjunction 0 with a cab signal or train control system of the type employing either steady or coded rail current. 7

In a typical system employing approach control of coders, the failure of a track relay of a 5 block to drop in response to the entrance of a train into that block means that that coder. for

supplying rail current to, that block 'does not start and the train in question receives a stopindication or control. Thus, a track relay failure V ,is manifested by an abnormal operation of the system. This feature is also true of the arrangement of this invention; and in addition to imposing restrictive control upon a train upon failure 7 7 of a track'relay to drop, any other train that may be following also receives a restrictive indication or control.

From the foregoing it can be seen that this invention provides an organization in which the de-energization of each track relay is accompanied by the de-energization of a special stick relay SB to impose the desired restrictive indication, said special stick relay remaining deenergized and maintaining such restrictive indication unless and until the next track relay in advance has been de-energized. Also, the approach control of the coding equipment, involving the code starting relays such as V0, is organized such that failure of a track relay and consequent failure of the special stick relay to be restored, prevents the supply of rail current to the following train, so that a restrictive indication is givenon a following train notwithstanding the failure of a track relay to become de-energized.

The specific organization and arrangement of relays and circuits shown and described is merely illustrative of the underlying principles and nature of the invention; and various adaptations, modifications, and additions may be made in this specific embodiment without departing from the invention.

What I claim is:

1. In a signaling system of the continuous inductive control type, the combination with blocks having track relays, of means associated with each block and automatically de-energized by the de-energization of the track relay of the corresponding block, said means when de-energized being restored only if the track relay of the next block in advance is tie-energized, and control means for supplying rail current to each block rendered efiective only if said means for that block is energized at the time the track relay for that block is first de-energized by an entering train.

2. In a system of signaling for railroads provided with blocks each having a track relay comprising, a safety relay associated with each block and automatically de-energized by the de-energization of the track relay of that block, said relay when once de-energized being again energized only if the track relay of the next block in advance is subsequently de-energized, a coder for intermittently supplying rail current to each block, and approach control means for initiating the operation of each coder and for establishing a circuit to supply rail current to that block, said approach control means being rendered efiective only if said safety relay is energized at the time the track relay of the corresponding block is first de-energized by an entering train.

3. In a cab signal or train control system of the continuous inductive control type, a safety relay associated with each block and energized only if the track relays of that block and the block next in advance have been successively de-energized by some preceding train, and approach control means for supplying rail current to each block, said approach control means being rendered effective only if said safety relay of that block is energized at the time the track relay of that block is first de-energlzed by an entering train.

4. In a system of continuous inductive control for railroads, the combination With a track divided into blocks each having a track relay, of means for supplying rail current to the track rails at the exit end of each block only if the track relays of that block and the next block in advance have been tie-energized successively by some preceding train.

5. In a system of continuous inductive control for railroads, the combination with a track divided into blocks each having a track relay, of means for supplying rail current to the track rails at the exit end of each block upon occupancy of the block only if the track relays of that block and of the block next in advance have, previously to the occupancy, been at the same time, respectively energized and de-energized.

6. In a system of signaling for railroads provided with blocks each having a track relay comprising, a safety relay associated with each block and automatically de-energized by the de-energization 0f the track relay of that block, said relay when once de-energized being again energized only if the track relay of the next block in advance is subsequently de-energized, a coder for intermittently supplying rail current to each block, and approach control means for initiating the operation of each coder and for establishing a circuit to supply rail current to that block, said approach control means being rendered effective only if said safety relay is energized at the time the track relay of the corresponding block is first tie-energized by an entering train, and wayside signals controlled by said safety relay.

WADE H. REICl-IARD. 

